A 78-year-old woman was attacked from behind by a robber wielding an umbrella, who knocked her to the ground and snatched her purse in San Francisco’s Bernal Heights neighborhood, officials said Thursday.

The robbery occurred about 8:50 a.m. on Wednesday on the 4000 block of Mission Street, police said.

The assailant, who was described as being about 20 years old, came up behind the victim and hit her with an umbrella, causing the her to fall, police said.

The suspect then grabbed the woman’s purse, stealing her money, and fled northbound on Mission Street.